Beiiming of hides and skins



Patented Mar. 5, 1940 PATENT OFFICE DELIMHNG 0F IHIDES AND SKINS William R.

Hill, Stamford, Conn, assignor to American Cyanainirl. Company, New York, N. Y.,

a corporation of Maine No Drawing. Application May 26, 1939, Serial No. 275,914

2 Claims.

This invention relates to the deliming of hides and skins by the use of hydroxy aminotriazines as deliming agents.

I have found that aminotriazines containing one or two hydroxy groups are very satisfactory deliming agents for removing lime from hides and skins during their conversion into leather. l/Vhen used for this purpose they are somewhat slower than such. commercially used deliming agents as lactic acid and ammonium salts, but they are much milder in action and will not injure the skin even when contacted therewith for long periods of time.

Thehydroxy aminotriazines are the members of the group consisting of ammeline, which is 1-hydroxy-3.5-diamino-2.4.6-triazine, ammelide,

' described class are white crystalline solids which are only slightly soluble in water, but which form water-soluble calcium salts. I have found, however, that ammeline possesses the most desirable deliming characteristics of any member of this group and my preferred .deliming agents contain this material, either alone or in admixture with ammelide and hydroxy aminotriazines of higher molecular weight. Since considerable quantities of ammeline are present in the crude mixture obtained as a by-product in the production of melamine from dicyandiamide, the use of these crude mixtures as deliming agents is also Example I 15 A dried goat skin was soaked in water for 24 hours and was then immersed in a lime bath containing an excess of lime for seven days. It was then unhaired, washed, drained and weighed.

The unhaired skin was placed in a paddle washer containing 400% of its weight of water and 10% of ammeline and washed overnight with continuous agitation by the paddle. At the end of this period the pH' of the solution was 7.7 and that of the skin was 7.0 as indicated by brom thymol blue. Both skin and solution were colorless to phenolphthalein and the skin was thoroughly delimed.

The 10% of ammeline used was a considerable excess, as was shown. by the presence of undis- 30 comprises immersing them in an aqueous disper- 1 sion containing ammeline.

WILLIAM H. HILL. 

